[Xapian-discuss] Search docs with terms that match a pattern

[Olly Betts]

On Tue, Apr 07, 2009 at 10:33:12AM +0200, David Versmisse wrote:
> I have once again a small question: Is it possible to search a pattern
> like "*foo*" ? I saw that we can use QueryParser::FLAG_WILDCARD but
> only with "foo*" patterns. Have you got a trick to do that ?

No, only trailing wildcards are supported.  To support simultaneous
leading and trailing wildcards without the performance sucking, we'd
need to maintain a copy of the termlist structured in a way which allows
efficient regexp searching.

> And an other question with wildcards: i tested FLAG_WILDCARD and the
> QueryParser, but i have some problems with special characters (by
> example "/"). Is it possible to use escape characters to do that? I
> tried "\/", but without good results. The problem is that your terms
> are often "id", or something like that, with a lot of special
> characters :-(

An id term makes a lot more sense as a boolean term rather than a
probabilistic one - it's not a word and you don't want it stemmed.  And
boolean terms can contain "/".

But wildcards on boolean terms aren't supported.  They could be, but a
boolean term can of course contain literal "*", so you'd need to support
some sort of escaping.  There's some discussion of that here:

http://trac.xapian.org/ticket/128

Cheers,
    Olly